Monday, February 17, 2014

CoCo 3 Upgrades: Hitachi 6309 CPU, 512KB RAM, PS2 keyboard

Installed a bunch of CoCo 3 upgrades from Cloud-9 Tech over the weekend:

I upgraded the old 68B09 CPU to the powerful Hitachi 63C09. This involved desoldering the old CPU and replacing it with a socket. I also put in a Pro-Tector+ board to protect the CPU from the inevitable torture I have planned for this thing (once I get all of my electronics gear out of storage and back in one place).

The Cloud-9 512K Triad upgrade board (the blue triangle) was trivial to install by comparison. Following the instructions, I removed the four old (128K) RAM chips, snipped a couple capacitors, and plugged it in:

Cloud-9 also sells a nice PS2-keyboard upgrade board which was an easy install (no soldering):

I'm currently scrolling the text screen up using a simple C routine. It's so embarrassingly slow right now (even at 1.89MHz 6309 native mode) that you can kinda see the scroll function move the lines up the screen. But this is fine for simple printf()-style debug output. I'm using this BSD-licensed tiny printf() for embedded applications.

I've also compiled in the DriveWire 4 assembly 115kbps/230kbps I/O routines into this test app, so I can do disk I/O without relying on OS/9 or the BASIC ROM routines. My plan going forward is to continue completely "taking over" the machine and just do my own thing (no OS at all). It should be easy to code up a DriveWire compatible I/O disk module (here's the DriveWire protocol specification).

About Me

Back in the day I worked for several years at Digital Illusions on things like the first shipping deferred shaded game ("Shrek" - 2001), software renderers, and game AI. Then, after working for Microsoft at Ensemble Studios for 5 years as engine lead on Halo Wars, I took a year off to create "crunch", an advanced DXTc texture compression library. I then worked 5 years at Valve, where I contributed to Portal 2, Dota 2, CS:GO, and the Linux versions of Valve's Source1 games. I was one of the original developers on the Steam Linux team, where I worked with a (somewhat enigmatic) multi-billionare on proving that OpenGL could still hold its own vs. Direct3D. I also started the vogl (Valve's OpenGL debugger) project from scratch, which I worked on for over a year. In my spare time I work on various open source lossless and texture compression projects: crunch, LZHAM, miniz, jpeg-compressor, and picojpeg.